1. Field of the Invention
This invention pertains to delineation and sign support devices having a deformable base which permits the device to be run over by a vehicle without damaging the vehicle, the sign, or the base. More particularly, it pertains to a removable support device which can be easily attached to different locationns at a road or ground surface.
2. Prior Art
Delineation and sign devices are placed at various locations for controlling and directing the flow of traffic. Such locations include concrete, asphalt and other paved surfaces, as well as road bridge surfacing, gravel, road base and dirt. Because of the extreme divergence of physical characteristics for each of these materials, it has been very difficult to find a single support base which is suited for implacement generally. For example some delineation devices are glued at their base to the pavement, whereas other devices are buried in the soil.
A common deficiency with most support bases adapted for holding a delineator or sign post in upright orientation is the inability of the base to be detached or implaced at will. This deficiency is particularly troublesome when the delineator or sign is repeatedly shifted between two or more locations. For example, morning traffic may require delineator devices directing traffic into numerous rush hour lanes; whereas evening traffic may require switching the delineation devices to increase the rush hour lanes in the opposing directions. Obviously, it is not feasible to adhesively apply such delineators on such a recurring basis because expense and time factors are prohibitive. A form of detachable base is required which enables a maintenance crew to quickly move the delineators from a first location to a second location without excessive effort.
Prior art approaches for detachable delineation devices have included the use of holes bored or pre-formed in the road surface which are readily adapted for receiving and releasing the delineator. Unfortunately, installation of such holes is expensive and typically permanent. Changes in traffic patterns, seasons of the year and other needs generally dictate against such permanent means of attachment of the delineator.
U.S. Pat. No. 1,337,947 illustrates a deformable delineator or sign support which has a domed shaped support base suitable for attachment to a paved surface. This reference discloses the prior art of attaching a support base or delineator to pavement wherein the base is bolted in place. Although the use of bolts enables the device to be removed at will, the process is time consuming and typically requires a threaded lug or other type of embedded nut for receiving the bolt and anchoring it to the pavement surface. Although the bolting of various types of delineator bases has continued in use, the limitations of (i) excessive time for implacement and removal, and (ii) high installation and maintenance expense constitute a long-felt need begging solution.
U.S. Pat. No. 2,719,214 illustrates an additional delineation device having a deformable base which is mounted to a receptacle pre-formed within a paved structure. The figures clearly illustrate the aforementioned problems of excessive installation time and expense.
A second problem which has troubled traffic engineers for years is the tendency of a flexible delineator to deform around the bumper of the impacting vehicle at higher speeds. With the increased speed of today's traffic, such problems associated with flexible delineator structures at impact have significantly increased. A significant deficiency associated with this problem is the "gripping - effect" which occurs as the flexible delineator structure deforms over the front of the vehicle and bumper. This initial deformation increases the frictional contact between the vehicle and delineator and tends to grab hold of the delineator and pull it free from its mounting structure. If the delineator is mounted on a paved surface by adhesive, the strength of the adhesive is typically exceeded and breaks free from the road surface. If, on the other hand, the delineator is mounted in the ground or in a back-filled condition, the delineator may simply be extracted from its buried position.
The tendency of flexible delineators to be torn free from their mounted locations creates a severe problem where the delineator is intended to be detachable. Intuitively, the easier the device is to separate from its base, the more likely such separation will occur under impact conditions which apply the same type of lifting stress. Consequently, the intended ease of detachability for the delineator has characteristically been inversely proportional with the rate of speed anticipated at impact between the vehicle and the delineator. In high velocity areas, the anchoring of the delineator is generally more permanent. Where slower speeds exist, such as in maintenance or construction zones, the sturdiness of attachment can be sacrificed in favor of portability. It will be apparent to those skilled in the art that similar opposing design comparisons can be made with respect to other properties unique to the field of delineation devices and their attachment to various types of surfaces. The foregoing examples are merely illustrative of numerous conditions which have remained unsolved for many years. As a consequence, highway engineers presently design delineators to meet the more important consideration of survivability in an operable condition, and sacrifice other conditions such as convenience in implacement or detachment.